Grinding machine



oct. 18, 1932. F, s, HAAS 1,882,814

' GRINDING MACHINE Filed May 27. 1930 3 Sheets-Sheet 1 m8181932. A RSHA'AS 1,882,814

I GRINDING MACHINE Filed May 27. 1930 5 Sheets-Sheet 2 my ll//l'lll/1111211011700)A fff/ Oct. 18, 1.932. F, s. HAAS 1,882,814v

GRINDING MACHINE Filed May 27. 1930 s sheets-sheet s l Patented Oct. 18,1932

uNiTEusTATEs PATENT: ori-uca .frnnnnarcx s.l mias, or oINcINNArI, omo', AssIGNon, B' uEsNE AslsIGNnEN'rs, To man HEALD MACHINE COMPANY, F "WQBCESTEB, MASSACHUSETTS, A COBPORATIO OF MASSACHUSETTS GRINDING MACHINE l1 1 Appupamnrmea :my a7, leso. serial no. erases.

- This invention relates tov improvements in f grinding machines and particularly to an improved structure for. truinor redressing the active face of grinding w eels.

In the `use"of`automatic production grinding machines use ismade of a sizing control tohold successive work pieces to the same exact size. At the present time the working tolerance is extremelysmall being in` many best condition. Furthermore, the high .pro-

duction standard of the present day requires the retruing or redressing of the face ofn the grinding wheel be done in a minimum of time and in the most expeditious manner.

It is, therefore, one of the principal objects of the present invention to provide an improved mechanism for`maintainng the sharp clean cutting face on a grinding wheel.

` Another `object of the invention Is the pro- 2 vision of automatic means -for automatically c retruing or redressing the active faceof the grinding wheel in a minimum of time without disturbing the setting y61E the machine or 3;) interfering with the constant production thereof.

' l Another object of the invention` is the pro'- vision of an improved wheeldia-inondingor retruing mechanism coupled inAwiththe 3'5 fnorm'alcyc'leof the machine so as to function at a. predetermined' point in the cycle thereof.

Afurther object of the invention is the provision of improved means capable of being ladjusted to vary the cycle of operation so that the surface of the grinding wheel` may be retrued or redressed` at the completion of each work piece, or afterthe completion of anydefinite number of work pieces.

Other objects and advanta es of the present .invention should be readlly apparent by reference totthe following specification considered in conjunction with the accompany-v ing drawings forming a part thereof, and it is to be understood that any modifications may be made in the exact structural details without departing from or exceeding the y from s irt of the invention, within `the scopeof t e appended claims.

In the drawings:

l Figure 1 isa'front elevation of a grinding machine embodyingthe improvements of this I invention.

Figure 2 is a rear elevational view of the device shown in Figure 1. i

`Figure 3 is a sectional view taken on line 3 3 of Figure 2.

F igure-4 is a sectional view taken on line 4 4 of Figure 3.

Figure 5 is a sectional view taken on line 5 5 of Figure 3.

Figure 6 is a sectional View taken on lin'e 6 6 of Figure 1.

Figure 7 is an enlarged view of the remov` ableftrip dog parts bein shown in cross section and forming a detail of the-invention. Figure 8 is a longitudinal sectional view through the trip mechanism,including'the electric operating switch, and

Figure 9 is a diagrammatic view showing they hydraulic and electric` circuits involved in the invention. l

Throughout the several views of the drawings similar reference characters are employed to denote the sameV or similar' parts. v

For purposes of illustration the improved, novel truing mechanism has been shown as appliedto an internal grinder 0r whole gen- '.erator. This machine may comprise a bed 10 having/formed on its upper endin horizontally spaced planes the Ways 11 and 12.

'Supported by the ways 11 is the grinding wheelhead 13 having a motor 14 coupled with spindle 15 for rotating the small or internal rinding wheel 16 at the desired rate. The liead 13 is adapted to be reciprocated lon tudinally of the bed 10 ong the ways 11 liy an hydraulic medium through a. piston 17 having. a piston .rod 18-coupled therewith in any suitable or desirable y,in a'nner. The piston 117 is contained vin a cylinder 19 through which it reciprocates u nder the influence of the hydraulic medium. This hydraulic medium is contained in a tank or sum con uit 21 by a. pump 22 being discharged the pump through conduit 23. A con- 20,'from which it is drawn through a.

.i to the valve 26 where it is directed through .conduit 29ste the main valve 30 for discharge through common discharge conduit 31 `back to the tank or sump 20.

The valve 26 has extending from it a stem 32 coupled with a reversmg lever 33, mounted exterior of a plate 34 on the front of the bed for rocking movement through a shaft 35. The plate 36 of the wheelhead M 13 is provided with a T-slot or the like 37 in wh1ch is adjustabl secured trip dogs38 and 39. yThe oppose abutting faces ofthe Ydogs 38 and 39are on oppositesides of thek lever 33 for-engagement therewith, to effect -the shiftin or rockin -`of the lever thereby .i to eiect a s ifting oft e valve 26 and a constant reverse lon itudinal movement of the wheelhead 13 an grindin wheel16. The

dogs 38 and 39 are adjustab thereby to vary the lengtlf of stroke of the wheelhead13 to permit the grinding wheel 16 to traverse the work throughout its entire length for breaking up grinding lines and the likethereon.

Supported by the bed 10 and guided by the guideways 12' 'for movement longitudinally of the bedtoward and from 'the wheelhead,

13 is a slide 40. The slide 40""is," provided ',with a transverse dove-tailed guide 41 'ref ceived in a similarly formed "dove-tailed' guideway-42 4formed in the base of work head 4.0k 43. kThe work head 43 supports afwork rest blade 44 having an angular to 45 onr which the work piece 46 is moun for rotation. On one side of the Work rest 43 is rotatably mounted a frictional driving and control 45v member: 47 for impartin rotation to, and controlling the rotation o the work piece46.

On the other side of the Work rest 44 is rotatably mounted a pressure member` 48 for holding the work piece 46 in frictional en` gagement with the Wheel 47 to insure the propier contact lbetween the wheel 47 `and wor The slide 40 and wheelhead 43 are adapted to be actuated longitudinally of the bed to"A an 'operating position adjacent the inding wheel-16 and to a position remote om the said grinding wheel to permit a replacement f of the work on the blade 44 at'the'completion of each work piece. This movement is imu parted to the said parts by hydraulic pres.-

`sure which passes from thepressure line 24 through a conduit 49 to a va1vecasing l50, enclosing a slide valve 51.` The slide valve 51 directs the medium through either a con- 5 duit 52 or 53 coupled with opposite ends of a The hydraulic medium with.

cylinder 54 in which a piston 55 isI located for i reciprocation therethrough. As shown in Figure 9, the medium passes from the casing 50through conduit 52 .to the right hand side of, piston 55 discharging the medium ahead ofV it through conduit 53 to the valve casing 50. The medium then passes from' the valve casing 50 through a. conduit 57'to the mainy valve 30 Where it is directed to the common discharge line 31 for return to the tank or sump '20. The piston 55 hasextending therefrom a piston rod 56 coupled with the slide 40, whereby the movement imparted to the piston 55 carries with it the said slide 40 and work head 43.

The valve 51 has extending from it a valve stem similar to the valve stem 32, which is coupled with, a rock shaft 58, having keyed to its end, exterior to the plate 59, a shift lever 60.v The shaft 58 is also pivotally coupled with a link 61 extending longitudinally of the bedalon the front face thereof, and

pivoted at'its ot er end with a link 62. The

lower end of the link 62 is pivoted to a block 63 and has protrudingfrom it toward thek Work head 43 a pinA or abutment adapted to l be engaged by`adjustable dogs 64 and 65. These dogs 64 and 65 are adjustablfy mounted ina T-slot 66 formed along the yace of the slide 40.` V

Automatic means, vnot shown, for gaging the size of the work lis employed for shifting the valve 51 in one direction at the completion yof each grinding operation to effect a withdrawal of the work head from the operative "position During the withdrawal Vof the wheelhead, an automatic ejector 67 removes 1 through a feeding mechanism, indicated diagrammatically in Figure 1 by the numeral 68, to feed .the workpiece into the grinding wheel and effect a stock removal therefrom.

ead is repeated to replace said work piece `with an unfinished one. Y

As was noted above, the active surface of the grinding wheel 16 may be retrued or redressed after the completion of the grinding Operation on each piece, or this retruing or the bore in the work piece-and the Work head 43 is actuated transversely of the plate 40 lit redressing mayeoccur after the completion of a certain num r of pieces. To this end the wheel head 43 has mounted thereon a cylin.- der`70, containin for reciprocating moves ment therethrough, a Vpiston 71. A piston rod 72 extends from the piston/71 and 'hasa post 7 3 secured in itsrf'orward end supporting a diamond or other truing tool 7 4. The piston 71 is actuated by the hydraulic medium which enters same through inlet port 75 from a conduit 76. The other end of the cylinder 70 has a port 77 coupled with a conduit 78. The medium is directed into the conduitfTS` by the main valve from a conduit 7V9 extending from the pressure'line 23. The dis-` charge from the conduit 7 6-is likewise directed by the valve 30 to a conduit 8O for return to the sump or tank 20.

To determine whetherone or more work pieces are to 4be inishechbetween the retruing or redressing operati nsA on the face of the grinding wheel, the fol owing mechanism isemployed. The work head slide40 is prvided on its rear face, as shown in Fi urel ably mounted a,y dog 82 having an inclinedV face 83 for engagement with roller 84 of plunger 85.. The plunger 85 is vertically, shiftablymounted in a housing or casing 86 secured to the rear wall of the bed 10. A

lever 87, pivotallymounted at 88 to the Wall of the casing 86 having a tongue 89 extending therefromfis 'received within a slot 90 formed intermediate the ends of the plunger 85. A crank 91 extends fromvthe pivot shaft 88 for rocking movement therewith, and has pivoted thereto, at 92, a pawl` 93. The lever 87 is limited in its upward movement 'in one direction by an adjustable abutment stop 94, and at its other en d contacts a spring pressed plunger 95 for returning the lever 'to its normal position together with the. plunger 85.v

The pawl 93 overlies a ratchetplate 96'formed integral with a sleeve 97 loosely mounted Von pivot shaft 88. Secured for movement cam periphery a lug 99. A spring has one-end secured to the pawl 93 and the other end with the ratchet plate 96 and sleeve 97'is `fa late 98 having extending from its with` a fixed `part of the mechanism or hous`` vin 86,-and maintains Contact between the point of the pawl and .the teeth of the ratchet.

, While but a single"projecting point 99 has on plate 96 v1;.ndadvance thed'cam plate 98d correspondingly. of the cam plate 98 brings the projection or lug 99 thereon, into engagement with, for

'depressing a ,plunger 101 to yclose a switch 102 carried by the housing orcasing 86. As shown diagrammatically'in- Figure 9, this switch 102is coupled With a solenoid -103 lthrough electric wires 104` and 105 with the m/ain electrical 1eads'106 and 107. As shown inFigure, the' solenoid 103 is connected by a strap 108 `with a valve shift leve-r 109, pivot- This intermittent rotation edat 110 in a'housing 86.v This housing 86 encloses the main valve 30 to which theA valve shift arm 109 is connected4 for move` ment thereby. This shifting of the valve 30,

as .seen in F igure 9, through the solenoid 103 will'lbe to the right, thereby cutting off the' fiow ot the discharge medium through` the conduit 49 and stoppingr further actuation of 'the work head 43. At the same time the medium being discharged through'valve\26 l and conduit 29-wi1l pass through a .conduit 112 instead of through conduit 31A. The conduit 112 is provided with a choke or needle valve 1120 to restrict the iow therethrough, and cause a corresponding/ slow movement ment of the wheel head 1 3 must necessarily be of'the wheel headand 'Wh/'eel past the diai mond. It will be appreciated that'th'e moveextendedto permit the 'entire face of the Wheel to pass across the point of theynow stationary diamond or truing tool. 'To this end the dog. 38 is provided with a solenoid -114, from which-'the wires 115 and 116 extend, being broken by la' switch 117. The

switch 117, as shownydiagrammatically in Figure9 and structurally in ligiire 5, comprisesl a yieldable mounted depressible plunger,118,l cooperating wlth a camface -119 formed on the .upper end of the valve Y shift lever 109. This'closing ofthe switch 117 establishes an electrical ci cuit including 1 'l the solenoid 114, whereby the og 38 is raised out of the path of the shift lever 33-so thatv the wheel head 13 must travel until the dog 120 of the wheel head engagessaid lever to` effect a reversal of the valve, thereby extending the stroke ot the wheel head 13 to vpass the entire active surface of the grinding wheel 16 across the point of the diamond or other truing tool 74.

' Means may also be provided to permit the'.

grindingwheel to make a single pass or a 7 plurality of-passes across the truing tool'be'- .fore the said truing tool isretracted, and the normal stroke of the wheel head 13"estab lished to again continue the grinding operation. To this end a T shaped slot 121i`s `formed in the rear face of the wheel head 13 for anadjustable do 122, which similar to gagement with and depression of a plunger Ature withthe plunger 85 for intermittently .the dog. 82, has an `inclined' face 123 for ena cam plate 129. This cam plate 129 is provided with one or more projections 130 to depress a plunger 131 to close a switch 132.

The, switch 132 is electrically connected through lines 133 and 134 with a solenoid 135 having itsmovable core pivotallykconnected to the other end of link 108 for reversely shifting the valve shifter lever 109 and correspondingly shifting the main valve 30. At

.this time the cam face 119 is removed from the plunger 118, thereby opening theV switch 117 to break the electric circuit which includes the solenoid 114, permitting the dog 38 under influence ofspring 38a .topreturn to its normal position.

The operation of the-device is as follows: assuming a. work piece to have been just completed and, through the size control device, 4effected a movement of the work head 43 to the rear or away from the wheel head. As' suming further the parts within casing 86 are in the position shown iii Figure 5. The^re tracting movement of the work head 43, will, through the dog 82, depress plunger 85 to advance the cam plate 98 for closing switch 102. This switch 102 completes the electrical circuit including the solenoid 103 to shift the main valve 30 to the position for stopping further movement of the work head 43 and locking same in this position. 'At this time the hydraulic medium passes through the conduit 76 to shift the piston 71 for positioning the diamond or other. truing tool iii' the line of movement of the active`faoe of Athe grinding wheel 16. At the time of shift- `l6 passes the said diamond or truingitool 74.

The wheel head 13 reciprocates the full'stroke permitted by the dogs 39 and 120, and each time the dog 122 on the^rear ofthe said wheel head depresses the plunger 124 for advancing the cam `plate 129, and assoon as the cam point 130 thereon engages and depresses plunger 131, the switch 132 is closed, com-I pleting an electrical circuit which includes the solenoid 135 and reversely shifts the main valve 30. The number of passes of the Wheel head 13 and grinding wheel 16 across the diamond or truing tool is determinedby the number of cam points projecting from the cam plate 129, or by the setting of an /adjustable stop associated therewith which iS similar in construction and function to the stop 94. f

As soon as the main valve 30 has been actuated to its normal operating position, the work head 43 again is set in motion simultaneously with the reverse actuation of piston 7l and retractionof diamond or truing ytoolf 74. The normal cycle of the machine then continues until the plunger 85 has again been depressedto the necessary or desired number of times for again retruing or resurfacingy theactive surface of the wheel 16. The shifting of the valve 30 and lever 109 opened the switch 117, thereby breaking-the electrical circuit which included the solenoid 114, permitting the dog 38 under the influence of its spring to descend into the path of the lever 33 to shift the said lever at each 'end of the short normal grinding stroke.

What is claimed is:

1. In a grindin machine the combination of a bed,.a grinding wheel support carried thereby and reciprocable lon itudinally thereof,` awork support carried by the bed and reciprocable longitudinally thereof toward andfrom the grinding wheel support, a grinding Wheel rotatably carried by the grinding wheel support, means recipro- `cating t ev grinding wheel support through a short normal grinding stroke, means reciproeating the ywork support through a normal work receiving and ejecting stroke, means for interrupting the movement of the work support, means for extending the stroke of the grinding wheel support, and means carried by the work support for resurfacing the Fgrinding wheelat the time the movement of the work head is stopped and the movement of the grinding wheel support is extended.

2. I-n a grinding machine the combination of a bed, apair of slides supported by the bed and movable toward and from one another, hydraulic means for actuating the slides, one of the slides rotatably supporting a grinding wheel, the other slide rotatably supporting a work piece to be operated upon by the grinding wheel, means for stopping one of the slides vat a predetermined point, andy means carried by said slide for resurfacing the active face of the grinding wheel.

3. In a grinding machine the combination of a bed, a pair of slides carried thereby and reciprocable longitudinally thereof, means on one of the slides for rotatablysupporting a grinding wheel, means on the other slide for rotatably supporting a work piece to be operated upon by the grinding wheel, means A thereof, a grinding wheel rotatably mounted in the wheel head, a work head carried the support and longitudinall recprocable thereof, a trueing tool carrie by the workl head having an operative and aninoperative position, hydraulic means for effecting the reciprocation of the work head and wheel ..head, and means for simultaneously stopping the movement of one of the heads andactu- Aating the trueing tool to its operative position. 5. 'In a grinding machine the combination With a bed `or support havingformed thereon a pair of guide Ways, a Wheelihead rotatably carrying a grinding Wheel andv supported by one of the ways for movement longitudinally of the bed, a work head supported by the other way for movement longitudi:

I 'shifting the main "valve controlled by the said heads forl stopping the movementof oney of them While permitting the movement of the other. i

6. In a grinding machine the combination with a bed or support having formed thereon a pair of guide Ways, a wheel head rotatably carr in a rindin wheel and supported by g1' y g g g slide adjustable from a position -adjacent theone of the ways for movement longitudinally of, the'` bed, a work head supported by the other way for movement longitudinally of the bed toward and from the grinding wheel, an hydraulic circuit for actuating the wheel head and Work head, a main valve in the circuit, supplemental reversing valves in the circuit one for the Wheel head and one `for the Work yhead each` reversing the movement -of its respective head, means or shifting the main valve controlled by the said heads for stopping the movement of one of them While permitting the movement of the other, and mea-ns for redressing the activesurface of the grinding wheel at the time one of 'the said heads is held stationary. f

7. Ina device of the class described the combination ofa bed, a'pair of slides carriedl thereby and reciprocable longitudinally thereof toward and'fron one another, onel of said slides supporting a rotating grinding Wheel and theother slide supporting a retrueing tool for operation on the active 'face of the grinding Wheel, hydraulic means for actuating the slides, hydraulic means for adjustthe the retrueing tool from an inoperative to' an operative position, said hydraulic means ,including a valve, and meanscontrolled by the reciprocating movement of the slides for shifting thevalve tosimultaneously stop,the

movement of one ofthe slides and adjust the retrueing tool vto the operative position' forretrueing the active face of the i wheel. 4

'8. In a device of the class described the combination of a bed, a pair of slides carried thereby j and reciprocable lon 'tudinally thereof toward and from one anot er, one of saidvslides supporting a rotating grinding Wheel and the other slide supporting a retrueing tool for operation on the active face of the grindingwheel, hydraulic means for actuating the'slides, hydraulic means for adjusting the retrueing tool from an inoperative to 'itsL an operative position, said hydraulic means including a valve', means controlled bythe reciprocating movement of the slides for` shifting the valve to simultaneouslytop the movement of one of the slides and adjust the retrueing tooleto the operative position for retrueing the active face of the grinding wheel, andl means operable by the remaining slide forreversely shiftin the valve to re-i tract the retrueing tool an ei'ectthe normal reciprocation of the previously stopped slide.

9, In a inding machin'e the combination of a be a grinding wheel supported by the bed and reciprocable through a normal work grinding stroke relative thereto, means `for 'extending .the normal stroke of the grinding wheel,l a work supporting slide reciprocable longitudinally of the bed to present a Work piecefin operative association with the inding wheel, a trueing tool carried by the grinding wheelto retrue the active surface thereof tola position remote from the grinding wheel a piston supporting the trueing tool, a reci, rocable hydraulic motor for actut ating the s de, hydraulic means for actuating the piston and motor, and means operable by the slide for operating the grinding Awheel stroke extending means and for actuating the -trueing tool. y i

10. In a grinding machine the combination of a bed, a pair of slides carried thereby'and reciprocable longitudinally thereof toward and' from one another -one of the slides rotatably supporting a grinding wheel, the other,

slide supporting a cylinder, a piston reciprocable through the cylinder, a retrueing tool carried`b the iston for retrueing the active face of t e grinding wheel when the piston l is in its forward position, hydraulic means for recip'nocating the slides, through a normal' .wor g stroke, `means for extending the grinding wheel slide during the 11. In a grinding-machine the combination las iso

no f

j tool, an "15 pistons, a eonduitfor the medium, a valve in of a bed, a grinding wheel Slide roiatabiy supporting a grinding Wheel and translatable longitudinally ofthe bed, a Work supporting slide carried by the bed and translatable 1onv 5 gitudinally thereof/ toward r andl from the grinding wheel to operatively associatel the work piece carried thereby with the said grinding wheel, a retrueing tool carried b the work slide having a/position adjacent the active face of the grinding Wheel for retrueing same and an inoperative position remote therefrom, a deprssible plunger carriedby the bed in the path of movement of thework supporting slide, an hydraulic circuit including an hydraulic medium for actuating the slides and for positioning the retrueing tool, a valve controlling the flow of the medium, andmeans operable by the` depressible plunger for shifting the 'valvesto control the How of the hydraulic medium therethrough.

y 12. In a grinding machine the combination of a bed, a wheel head carried thereby and translatable longitudinally -thereof, a vvorkl l l head carried by the bed and translatable lon- 215 gitudinally thereof tovvard and from `the wheel head, a grinding Wheel rotatably supported by the wheel head, a retrueing tool carried by the work head having aposition adjacent the active face of the grinding wheel to retrue same and a position remote therefrom, apiston for actuating the wheel head, a second piston for actuating the work head,

a third lston for positioningthe `retrueing hydraulic medium for actuating the the conduit,-and electromagnetic means for shiftin the valve for controlling the flow of the lohydraulic medium through the conduit to simultaneously stop the translation of one of the slides and position the retrueing tool adjacent the active face of the grinding of the other slide.

Y 13. In a grinding machine the combination of a bed a wheel head ycarried thereby and translatable longitudinally thereof, a work head carried by the bed and translatable longitudinally' thereof toward and from the wheel head, a grinding wheel rotatably supported bythe wheelhead, a retrueing tool carried byuthe work head having a position adjacent theactive face of the grinding wheel tg retrue same and a position remote there- A from, a pistonfor actuating the-wheel head,A a second piston for actuating the'work head,

wheel while permitting continued translation wheelhead, a grinding Wheel rotatably supportedbythe wheelhead, a retrueing tool carried by the work head having apposition adjacent the active face of the grinding Wheel to retruey same and a position remote therefrom, a piston for actuatingthewheel head, al

second piston, for actuating lthe Work head, a third piston for positioning the retrueing ytool,'anlhydraulic medium for actuating the pistons, a conduit forthe medium,l a valve in the conduit, electromagnetic means for shifting the valve for controlling the flow of the hydraulic mediuml through the ,/conduit to simultaneously stop the translation of one of the slides and position the retrueing tool adjacent the active face of the grinding Wheel while permitting continued translation of the other slide, said means including adepressible plunger operable by the Work head, an intermittently rotatable cam operatively connected with the plunger, a circuit breaker adapted to ,be closed by the cam, and means carried by the cam for determining the number of passes of the work head before the said circuit breaker is closed.

15.. In a grinding machine the combination of a bed', a pair of slides carried thereby and translatable longitudinally lthereof toward s Y and from one another, aa rotating grinding Wheel carried by one ofthe slides, means for rotatably supportinga Work piece carriedby the other slide, a retrueing tool carried by the work supporting slide projectable from a position remote from the active face of the wheel to a position adjacent thereto, automatic means for positioning the retrueing tool adjacent the active face of the grinding Wheel to retrue same at 'a predetermined time, and means operable by the work supporting slide for operating the last named means.

16. In a rinding machine the combination of a beni a pair of slides carried thereby and translatable longitudinally thereof to- Ward and from one another, a rotating grinding wheel carried by one of the slides, meansfor rotatably supporting a Work piece carried by the-other slide, a retrueing tool carried by the Work supporting slide projectablc ,from a position remote fromthe active face v'of the Wheel to a position adjacent` thereto, automatic means for positioning the retrueing tool adjacent the active face of the grind- 'ing wheel to retrue same at a predetermined time, means operable by the work supporting slide for operating the last named means,

llO

and means operable by the grinding Wheel uplporting slide for retracting the retrueing 17. 'In a grinding machine the combination of a bed, a slide carried by the bed rotatably supporting a grinding wheel, means for constantly reciprocating the grinding wheel slide through a normal working stroke, a second slide carried by the bed rotatably supporting a work piece, means for intermittently reciprocating the work supporting slide in cyclic sequence through a normal Working stroke to present a Work piece in operative kassociation with the grinding Wheel and to remove ittherefrom, a retrueing tool carried by the'work supportin slide having a kposition adjacent the active ace of the grinding wheel and a position remote therefrom, means extending vthe normal working stroke of one of the slides during the retrueing of the active face of the 'grinding Wheel, and means operable by one of the slides for determinin the number of cyclic strokes to be made y the Work supporting slide before the retrueing of the active face of the grinding wheel`and for positioning the retrueing tool I .adjacentthe face of the grinding Wheel and simultaneously operatingthe means for extending the normal 'Working stroke of one f the slides. p

18. In a grinding machine the combination of a bed, a slide carried by the bed rotatably supporting a grinding wheel, means for-constantly reciprocating the grinding wheel slide through a normal working stroke, a second slide carried by the bed rotatably supportinga work piece, means for intermittently reciprocating the 'work supporting slide in cyclic sequence through a normal working ,stroke to` present a work piece in o era-tive association with the inding" 1v eel and to remove it there rom, a retrueing took carried by the Work supporting slide having a position adjacent the active face of the grinding wheel and a position remote therefrom,

means extending the-normal working stroke of one of the slides during the retrueing of the active face of the grinding Wheel, means operable by one of the slides for determining the number of cyclic strokes to be made by the work supporting slide before the retrue- -mg of the active face ofthe grinding wheeland for positioning'the retrueing tooladjacent the face of the grinding wheel and si multaneously operating' the means .for extending the normal Working stroke of one of the slides,

and means operable by the other slide for determining t e number of passes the retrueing tool and grinding wheel make` relative one to the other. .l

19. In a device of the class described the combination of a' bed or support, a grinding Ivvheel carried thereby and reciprocable longitudinally thereof, a Work piece support andreans for re-establishing the operating cycle. l

20. In a grinding machine-the combination of a bed, a pair of slides carried -thereby `and shiftabl'e relative thereto `toward and.

from one another, a grinding Wheel carried by one of the slides', a truing tool associated with the vother-slide, means for actuating said slides at normal Working rates, means for shifting the truing tool from a point L-remoe from the grinding Wheel to a point infline with the movement of the grinding Wheel `for retruing the face thereof, and means for stopping the movement of one of the slides and changing the rate of movement of the remaining slide to effect a traverse of the tool and wheel relative to one another at a ratebelow the normal working rate.`

21. In a grinding machine the combination of a bed, a pair of slides carried thereby and shiftable relative thereto toward and from one another, a grinding wheel carried by one ofthe slides, a truingtool associated with ythe other slide, means for actuating said slides at normal working rates, means for shifting the truing tool from ya point and :shiftable relative thereto toward and from one another, a grindingwheel carried v `by one of the slides, a truing tool associated "with the others'lide, means for actuating said 4slides abnormal working rates, means for shifting the truing tool from a point remote fromvthe grinding wheel to a point in line with the'movement of the grinding wheel for r`etruing the face thereof,- and means for stopping the movement of one of the slides and changing the rate of movement of the remaining slide to eect a traverse of the tool and Wheel relative to one another at a rate "below the normal Working rate, said means including a valve for controlling an hy-l draulic `circuit associated with the shiftable parts, electro-magnetic means for shifting` the valve, and means carried by the slide for energizing the `electro-magnetic means to -eifect a movement of the lvalve.

" tion of a beda pair of slides carried thereby 110 v 23.,In a grinding machine the combination of a bed, a pairof slides carried thereby and shiftable Vrelative thereto toward and` from one another, a grinding wheel carried-v by one of the slides, a truing tool associated y with the other slide, means for actuating said slides at normal working rates, means for shifting the truingtool from a. point remote from the grinding wheel to a point in line with the movement of the grinding Wheel for retruing the face thereof, means for stopping the movement of one of the slides and changing' the rate of movement of the remaining slide to effect a traverse of the tool and Wheel relative to one another .at a n i rate below the normal working rate, said means including a valve for controlling an hydraulic circuit associated with the shiftable parts, electro-magnetic means for shifting the valve, and means carried by the slide for energizing the electro-magnetic means to effect a movement of the valve, and additional imeans including electro-magnetic' means for shifting the valve to return `the' parts to their normal Working positions, and v means carried by the slide for energizing the said electro-magnetic means.

In` testimony whereof I ax my signature.

FREDERICK S. HAAS. 

